Most young women with breast cancer appear to undergo genetic testing for mutations in the BRCA1 and BRCA2 genes, according to results of a cross-sectional analysis of study data.

These data indicate that most women are following National Comprehensive Cancer Network guidelines that suggest women aged younger than 50 years when diagnosed with breast cancer undergo genetic testing.

Shoshana M. Rosenberg, ScD, MPH

However, results also showed that women found to not carry either mutation are still choosing to undergo a bilateral mastectomy despite having a low risk for breast cancer in the unaffected breast.

“We know that developing breast cancer can be especially anxiety provoking in young women,” Shoshana M. Rosenberg, ScD, MPH, instructor in medicine at Dana-Farber Cancer Institute, said in a press release. “They may have a sense that because they weren’t ‘supposed’ to develop breast cancer at such an early age, they want to feel that they’re doing everything possible to prevent another occurrence.”

Rosenberg and colleagues evaluated data from the ongoing prospective Helping Ourselves, Helping Others: Young Women’s Breast Cancer Study. This analysis included a cohort of 897 women aged 40 years or younger who were diagnosed with breast cancer between Aug. 1, 2006 and Dec. 31, 2013 at nine participating academic and community hospitals in the U.S. and Canada.

The researchers sought to evaluate how patients’ concerns about genetic risk and the use of and results from genetic testing affected their subsequent treatment decisions.

Additionally, the investigators aimed to gain an understanding as to why some young women did not undergo genetic testing despite clinical recommendations to do so.

Overall, 87% of the women in the cohort reported having BRCA testing within 1 year following a breast cancer diagnosis (mean age = 35.3 years for tested women, 36.9 years for untested women; P < .001).

The frequency of genetic testing increased over time. Of the 163 women diagnosed in 2006 or 2007, 117 (71.8%) reported testing. However, of the 275 women diagnosed in 2012 or 2013, 264 (96%) reported testing (P < .001).

Among the women who reported forgoing genetic testing after diagnosis, 31.6% said they did not have the discussion about the potential for a genetic mutation with their doctor or genetic counselor. An additional 36.8% reported that although they had not been tested, they were still considering it in the future.

Of 831 women who were tested and reported a positive or negative result, 29.8% said that knowledge or concern about genetic risk for breast cancer influenced their treatment decisions. Among these women (n = 248), 76 mutation carriers (86.4%) and 82 noncarriers (51.2%) chose to have a bilateral mastectomy (P < .001).

With so many non-BRCA carriers opting for a bilateral mastectomy, there “might [be] a need for better communication of their relatively low risk for developing cancer in the other breast,” Rosenberg said.

Limitations of this study included that most women would have undergone testing when Myriad Genetics was the only commercial laboratory offering clinical testing, and that testing for BRCA1 and BRCA2 was the only available option. Expansion of testing options to include whole-genome sequencing and multigene panels has changed the current pattern of testing.

Additionally, the generalizability of these data may be limited as most patients in the cohort were insured or treated in academic cancer center settings.

Still, the rise in testing may be attributable to the “Angelina Jolie effect,” or the increase in testing and prophylactic mastectomy following Angelina Jolie’s public announcement that she underwent bilateral mastectomy after learning she carried a BRCA mutation.

“Greater public awareness may have made women more likely to bring up the issue of genetic risk with their physicians, possibly resulting in more testing,” Rosenberg said in the release.

The fact that nearly half of the patients who were not tested indicated they and their physician did not think a BRCA mutation was likely despite guideline recommendations is “disconcerting,”

Kathleen R. Blazer, EdD, MS, LCGC, clinical assistant professor and the associate director of the cancer genetics education program at City of Hope in Duarte, California, and colleagues wrote in an accompanying editorial.

In agreement with the study researchers, Blazer and colleagues also stressed that many women without a BRCA mutation are opting for bilateral mastectomy.

However, on the whole, these data demonstrate an encouraging trend toward the integration of genetic cancer risk assessment into the standard of care in the past 2 decades, they wrote.

“The task remains to ensure that the benefits of [these assessments] reach more individuals and families, including those among underrepresented minorities, with economic disparities and in low-to-middle income countries,” they wrote. “As long as there is growing communities of practice and research collaboration, it won’t take another 20 years to get there.” – by Anthony SanFilippo

Disclosure: Rosenberg and Blazer report no relevant financial disclosures. One researcher reports research funding from Ambry Genetics and Myriad Genetics and consultant/advisory roles with Pfizer and Sequenom.

Perspective

PERSPECTIVE

Kathryn Evers, MD

How the use of genetic testing in young women with a diagnosis of breast cancer affects treatment decisions is an important issue on which there is a paucity of data. This paper begins to address this issue in a cohort of young women with breast cancer enrolled in the Young Women’s Breast Cancer Study.

Overall, it is encouraging that an increasing proportion of these women have been offered and received genetic testing as per National Comprehensive Cancer Network guidelines. As might be expected, genetic testing results had a significant impact on surgical choices, including the decisions to undergo bilateral mastectomies and removal of the ovaries. It is interesting that these results appear to have little impact on nonsurgical decision making, at least in the time period of the study.

These is encouraging data; however, these women all were treated at specialized cancer centers and represent only a subgroup of young women with cancer who have chosen to respond to the questionnaires sent. The percentage of young women with newly diagnosed breast cancer who are offered or obtain genetic testing outside of this milieu is unknown, and is certainly an area that begs for further study.